A famous environmental activist known for her work on climate change is Greta Thunberg. The Swedish teenager gained international recognition for her efforts to raise awareness about the climate crisis, beginning with her school strike movement, "Fridays for Future." Thunberg has spoken at numerous global forums, including the United Nations, where she has urged world leaders to take immediate and decisive action to reduce carbon emissions and combat climate change. Her passionate activism has inspired millions of people worldwide, particularly young people, to advocate for sustainable practices and policies, making her a prominent figure in the environmental movement.